首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2427篇
  免费   65篇
  国内免费   4篇
教育   1806篇
科学研究   117篇
各国文化   63篇
体育   248篇
综合类   1篇
文化理论   28篇
信息传播   233篇
  2023年   5篇
  2022年   11篇
  2021年   21篇
  2020年   45篇
  2019年   63篇
  2018年   98篇
  2017年   104篇
  2016年   96篇
  2015年   61篇
  2014年   91篇
  2013年   542篇
  2012年   80篇
  2011年   76篇
  2010年   60篇
  2009年   70篇
  2008年   87篇
  2007年   66篇
  2006年   70篇
  2005年   65篇
  2004年   47篇
  2003年   62篇
  2002年   66篇
  2001年   44篇
  2000年   31篇
  1999年   35篇
  1998年   22篇
  1997年   36篇
  1996年   35篇
  1995年   35篇
  1994年   19篇
  1993年   21篇
  1992年   22篇
  1991年   31篇
  1990年   20篇
  1989年   25篇
  1988年   16篇
  1987年   12篇
  1986年   14篇
  1985年   10篇
  1984年   14篇
  1983年   15篇
  1982年   22篇
  1981年   18篇
  1980年   6篇
  1979年   19篇
  1978年   10篇
  1977年   12篇
  1976年   12篇
  1975年   5篇
  1974年   7篇
排序方式: 共有2496条查询结果,搜索用时 17 毫秒
121.
122.
Regional investment in R&D, technological development and innovation is perceived as being strongly associated with productivity, growth and sustained international competitiveness. One policy instrument by which policy makers have attempted to create regional advantage has been the establishment of publicly funded research centres (PRCs). In this paper we develop a logic model for this type of regional intervention and examine the outputs and longer-term outcomes from a group of (18) publicly funded R&D centres. Our results suggest some positive regional impacts but also identify significant differences in terms of innovation, additionality and sustainability between university-based and company-based PRCs. University-based PRCs have higher levels of short-term additionality, demonstrate higher levels of organisational innovation but prove less sustainable. Company-based PRCs demonstrate more partial additionality in the short-term but ultimately prove more sustainable.  相似文献   
123.
What are the respective roles of indigenous and exogenous factors in the development of high-tech regions? Entrepreneurs and their start-ups have dominated Silicon Valley's economy in recent decades, but a different dynamic was at work from 1940 to 1965, when the Valley emerged as a formidable high-tech region. In key industries (electronics, semiconductors, computers, and aerospace) that defined Silicon Valley as a high-tech cluster during that period, companies based elsewhere played critical roles in planting the organizations that would - through the innovations they made, the technical talent they attracted, and the start-ups they spun off - help make the Valley the world's most admired and emulated high-tech region.  相似文献   
124.
In this study, we investigated the effects of two hydrotherapy interventions on match running performance and perceptual measures of fatigue and recovery during a 4-day soccer tournament. Twenty male junior soccer players were assigned to one of two treatment groups and undertook either cold-water immersion (5 × 1 min at 10 °C) or thermoneutral water immersion (5 × 1 min at 34 °C) after each match. High-intensity running distance (>15 km · h?1) and total distance covered, time spent in low (<80% maximum heart rate), moderate (80-90% maximum heart rate), and high (>90% maximum heart rate) heart rate zones, and rating of perceived exertion (RPE) were recorded for each match. Perceptions of general fatigue and leg soreness were recorded approximately 22 h after each match. There were decreases in both groups across the 4-day tournament for high-intensity running distance (P = 0.006, Cohen's d = 0.63), total distance run (P < 0.001, d = 0.90), time in high heart rate zone (P = 0.003, d = 0.90), and match RPE (P = 0.012, d = 0.52). Cold-water immersion was more effective than thermoneutral immersion for reducing the perception of leg soreness (P = 0.004, d = -0.92) and general fatigue (P = 0.007, d = -0.91), ameliorating the decrement in total distance run (P = 0.001, d = 0.55), and maintaining time in the moderate heart rate zone (P = 0.01, d = 1.06). In conclusion, cold-water immersion mediates the perceptions of fatigue and recovery and enhances the restoration of some match-related performance measures during a 4-day tournament.  相似文献   
125.
We compared cardiorespiratory responses to exercise on an underwater treadmill (UTM) and land treadmill (LTM) and derived an equation to estimate oxygen consumption (VO2) during UTM exercise. Fifty-five men and women completed one LTM and five UTM exercise sessions on separate days. The UTM sessions consisted of chest-deep immersion, with 0, 25, 50, 75, and 100% water-jet resistance. All session treadmill velocities increased every 3 min from 53.6 to 187.8 m x min(-1). Cardiorespiratory responses were similar between LTM and UTM when jet resistance for UTM was 50%. Using multiple regression analysis, weight-relative VO2 could be estimated as: VO2 (mLO2 c kg(-1) x min(-1)) = 0.19248 x height (cm) + 0.17422 x jet resistance (% max) + 0.14092 x velocity (m x min(-1)) -0.12794 x weight (kg)-27.82849, R2 = .82. Our data indicate that similar LTM and UTM cardiorespiratory responses are achievable, and we provide a reasonable estimate of UTM VO2.  相似文献   
126.
Ethics and Information Technology - Should we welcome social robots into interpersonal relationships? In this paper I show that an adequate answer to this question must take three factors into...  相似文献   
127.
The Vanderbilt Assessment of Leadership in Education (VAL-ED) provides educators with a tool for principal evaluation based on principal, teacher, and supervisor reports of principals’ learning-centered leadership. In this study, we conduct a known group analysis as part of a larger argument for the validity of the VAL-ED in US elementary and secondary schools. We asked superintendents to select the principals in their district who they believe in performance of their duties are in the top 20 % and the bottom 20 %. We ask how accurately VAL-ED scores can identify membership of the two known groups. Using a discriminant analysis, the VAL-ED places principals in the superintendent groups, on average, 70 % of the time for both elementary and secondary schools. Placement accuracy is greater for the top group than the bottom group.  相似文献   
128.
129.
130.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号